''Linux From Scratch'' (LFS) is a type of a Linux installation and the name of a book written by Gerard Beekmans, and as of May 2021, mainly maintained by Bruce Dubbs. The book gives readers instructions on how to build a Linux system from source. The book is available freely from the Linux From Scratch site.

Projects under LFS

''Linux From Scratch'' is a way to install a working Linux system by building all components of it manually. This is, naturally, a longer process than installing a pre-compiled

Linux distribution A Linux distribution (often abbreviated as distro) is an operating system made from a software collection that includes the Linux kernel and, often, a package management system. Linux users usually obtain their operating system by downloading one ...

. According to the ''Linux From Scratch'' site, the advantages to this method are a compact, flexible and secure system and a greater understanding of the internal workings of the Linux-based operating systems. To keep LFS small and focused, the book ''Beyond Linux From Scratch'' (BLFS) was created, which presents instructions on how to further develop the basic Linux system that was created in LFS. It introduces and guides the reader through additions to the system including the X Window System, desktop environments (

KDE KDE is an international Free software movement, free software community that develops free and open-source software. As a central development hub, it provides tools and resources that allow collaborative work on this kind of software. Well-know ...

GNOME A gnome is a mythological creature and diminutive spirit in Renaissance magic and alchemy, first introduced by Paracelsus in the 16th century and later adopted by more recent authors including those of modern fantasy literature. Its characte ...

, Xfce, LXDE), productivity software, web browsers, programming languages and tools, multimedia software, and network management and

system administration A system administrator, or sysadmin, or admin is a person who is responsible for the upkeep, configuration, and reliable operation of computer systems, especially multi-user computers, such as servers. The system administrator seeks to ensu ...

tools. Since Release 5.0, the BLFS book version matches the LFS book version. The book ''Cross Linux From Scratch'' (CLFS) focuses on

cross compiling A cross compiler is a compiler capable of creating executable code for a platform other than the one on which the compiler is running. For example, a compiler that runs on a PC but generates code that runs on an Android smartphone is a cross ...

, including compiling for headless or embedded systems that can ''run'' Linux, but lack the resources needed to ''compile'' Linux. CLFS supports a broad range of processors and addresses advanced techniques not included in the LFS book such as cross-build toolchains, multilibrary support (32 & 64-bit libraries side-by-side), and alternative

instruction set architecture In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ' ...

s such as Itanium, SPARC, MIPS, and

Alpha Alpha (uppercase , lowercase ; grc, ἄλφα, ''álpha'', or ell, άλφα, álfa) is the first letter of the Greek alphabet. In the system of Greek numerals, it has a value of one. Alpha is derived from the Phoenician letter aleph , whic ...

. The Linux from Scratch project, like

BitBake BitBake is a make-like build tool with the special focus of distributions and packages for embedded Linux cross compilation, although it is not limited to that. It is inspired by Portage, which is the package management system used by the Gent ...

, also supports cross-compiling Linux for ARM embedded systems such as the Raspberry Pi and BeagleBone. The boo
''Hardened Linux From Scratch'' (HLFS)
focuses on security enhancements such as hardened kernel patches, mandatory

access control In the fields of physical security and information security, access control (AC) is the selective restriction of access to a place or other resource, while access management describes the process. The act of ''accessing'' may mean consuming ...

policies,

stack-smashing protection Buffer overflow protection is any of various techniques used during software development to enhance the security of executable programs by detecting buffer overflows on stack-allocated variables, and preventing them from causing program misbehavior ...

, and address space layout randomization. Besides its main purpose of creating a security-focused operating system, HLFS had the secondary goal of being a security teaching tool. It has not been updated since 2011.
''Automated Linux From Scratch'' (ALFS)
is a project designed to automate the process of creating an LFS system. It is aimed at users who have gone through the LFS and BLFS books several times and wish to reduce the amount of work involved. A secondary goal is to act as a test of the LFS and BLFS books by directly extracting and running instructions from the XML sources of the LFS and BLFS books.

Requirements and procedure

A clean

partition Partition may refer to: Computing Hardware * Disk partitioning, the division of a hard disk drive * Memory partition, a subdivision of a computer's memory, usually for use by a single job Software * Partition (database), the division of a ...

and a working Linux system with a compiler and some essential

software libraries In computer science, a library is a collection of non-volatile resources used by computer programs, often for software development. These may include configuration data, documentation, help data, message templates, pre-written code and subro ...

are required to build LFS. Instead of installing from an existing Linux system, one can also use a Live CD to build an LFS system. The project formerly maintained the Linux From Scratch Live CD. LFS Live CD contains all the source packages (in the full version of the Live CD only), the LFS book, automated building tools and (except for the minimal Live CD version) an Xfce GUI environment to work in. The official LFS Live CD is no longer maintained, and cannot be used to build the LFS version7 or later. There are, however, two unofficial builds that can be used to build a 32-bit or 64-bit kernel and userspace respectively for LFS 7.x. First, a toolchain must be compiled consisting of the tools used to compile LFS, like GCC,

glibc The GNU C Library, commonly known as glibc, is the GNU Project's implementation of the C standard library. Despite its name, it now also directly supports C++ (and, indirectly, other programming languages). It was started in the 1980s by ...

, binutils, and other necessary utilities. Then, the

root directory In a computer file system, and primarily used in the Unix and Unix-like operating systems, the root directory is the first or top-most directory in a hierarchy. It can be likened to the trunk of a tree, as the starting point where all branches ...

must be changed, (using chroot), to the toolchain's

to start building the final system. One of the first packages to compile is glibc; after that, the toolchain's linker must be adjusted to link against the newly built glibc, so that all other packages that will make up the finished system can be linked against it as well. During the chroot phase,

bash Bash or BASH may refer to: Arts and entertainment * ''Bash!'' (Rockapella album), 1992 * ''Bash!'' (Dave Bailey album), 1961 * '' Bash: Latter-Day Plays'', a dramatic triptych * ''BASH!'' (role-playing game), a 2005 superhero game * "Bash" ('' ...

's hashing feature is turned off and the temporary toolchain's bin directory moved to the end of PATH. This way the newly compiled programs come first in PATH and the new system builds on its own new components.

List of packages in LFS

This is a list of the packages included in CLFS version 1.1.0. Unless otherwise noted, this list is applicable to all supported architectures. * Autoconf 2.61 * Automake 1.10.1 *

Bash Bash or BASH may refer to: Arts and entertainment * ''Bash!'' (Rockapella album), 1992 * ''Bash!'' (Dave Bailey album), 1961 * '' Bash: Latter-Day Plays'', a dramatic triptych * ''BASH!'' (role-playing game), a 2005 superhero game * "Bash" ('' ...

3.2 *

Documentation 3.2 * Bin86 (x86_64 non-multilib only) * Binutils 2.18 *

Bison Bison are large bovines in the genus ''Bison'' (Greek: "wild ox" (bison)) within the tribe Bovini. Two extant and numerous extinct species are recognised. Of the two surviving species, the American bison, ''B. bison'', found only in North Ame ...

2.3 * Bzip2 1.0.4 *CLFS-Bootscripts 1.0pre10 * Coreutils 6.9 * DejaGNU 1.4.4 * Diffutils 2.8.7 *

E2fsprogs e2fsprogs (sometimes called the e2fs programs) is a set of utilities for maintaining the ext2, ext3 and ext4 file systems. Since those file systems are often the default for Linux distributions, it is commonly considered to be essential software. ...

1.40.4 * Elftoaout 2.3 (Sparc and Sparc64 only) * Expect 5.43.0 * File 4.23 * Findutils 4.2.32 *

Flex Flex or FLEX may refer to: Computing * Flex (language), developed by Alan Kay * FLEX (operating system), a single-tasking operating system for the Motorola 6800 * FlexOS, an operating system developed by Digital Research * FLEX (protocol), a comm ...

2.5.35 * Gawk 3.1.6 * GCC 4.2.4 * Gettext 0.17 *

Glibc The GNU C Library, commonly known as glibc, is the GNU Project's implementation of the C standard library. Despite its name, it now also directly supports C++ (and, indirectly, other programming languages). It was started in the 1980s by ...

2.7 * Grep 2.5.3 * Groff 1.19.2 *

GRUB Grub can refer to Grub (larva), of the beetle superfamily Scarabaeoidea, or as a slang term for food. It can also refer to: Places * Grub, Appenzell Ausserrhoden, Switzerland * Grub, St. Gallen, Switzerland * Grub (Amerang), a hamlet in Bavaria, ...

0.97 * Gzip 1.3.12 * Hfsutils 3.2.6 (PowerPC and PowerPC64 only) *Iana-Etc. 2.20 *Inetutils 1.5 * IPRoute2 2.6.23 *Kbd 1.13 *

Less Less or LESS may refer to: fewer than,: not as much. Computing * less (Unix), a Unix utility program * Less (stylesheet language), a dynamic stylesheet language * Large-Scale Scrum (LeSS), a product development framework that extends Scrum Other ...

418 * LILO 22.8 (x86_64 non-multilib only) *

Libtool In computer programming, GNU Libtool is a software development tool, part of the GNU build system, consisting of a shell script created to address the software portability problem when compiling shared libraries from source code. It hides t ...

1.5.26 * Linux 2.6.24.7 *

GNU m4 m4 is a general-purpose macro processor included in most Unix-like operating systems, and is a component of the POSIX standard. The language was designed by Brian Kernighan and Dennis Ritchie for the original versions of UNIX. It is an extensio ...

1.4.10 * Make 3.81 *Man 1.6e * Man-pages 3.01 *Mktemp 1.5 *Module-Init-Tools 3.4 * Ncurses 5.6 * Parted 1.8.8 (PowerPC and PowerPC64 only) *

Patch Patch or Patches may refer to: Arts, entertainment and media * Patch Johnson, a fictional character from ''Days of Our Lives'' * Patch (''My Little Pony''), a toy * "Patches" (Dickey Lee song), 1962 * "Patches" (Chairmen of the Board song) ...

2.5.9 * Perl 5.8.8 * PowerPC Utils 1.1.3 (PowerPC and PowerPC64 only) *Procps 3.2.7 *Psmisc 22.6 * Readline 5.2 * Sed 4.1.5 * Shadow 4.1.2 *Silo 1.4.13 (Sparc and Sparc64 only) * Sysklogd 1.5 *

Sysvinit In Unix-based computer operating systems, init (short for ''initialization'') is the first process started during booting of the computer system. Init is a daemon process that continues running until the system is shut down. It is the direct ...

2.86 * tar 1.20 *

Tcl TCL or Tcl or TCLs may refer to: Business * TCL Technology, a Chinese consumer electronics and appliance company **TCL Electronics, a subsidiary of TCL Technology * Texas Collegiate League, a collegiate baseball league * Trade Centre Limited, a ...

8.4.16 * Texinfo 4.11 *Tree 1.5.1.1 * Udev 124 *

Util-linux-ng is a standard package distributed by the Linux Kernel Organization for use as part of the Linux operating system. A fork, (with meaning "next generation"), was created when development stalled, but has been renamed back to , and is the offic ...

2.14 *

Vim Vim means enthusiasm and vigor. It may also refer to: * Vim (cleaning product) * Vim Comedy Company, a movie studio * Vim Records * Vimentin, a protein * "Vim", a song by Machine Head on the album ''Through the Ashes of Empires'' * Vim (text ed ...

7.1 *

7.1 language files (optional) * Yaboot 1.3.13 (PowerPC and PowerPC64 only) * Zlib 1.2.3

Standard build unit

A "standard build unit" ("SBU") is a term used during initial bootstrapping of the system, and represents the amount of time required to build the first package in LFS on a given computer. Its creation was prompted by the long time required to build an LFS system, and the desire of many users to know how long a source tarball will take to build ahead of time. As of Linux From Scratch version 10.1, the first package built by the user is GNU binutils. When building it, users are encouraged to measure the build process using shell constructs and dub that time the system's "standard build unit". Once this number is known, an estimate of the time required to build later packages is expressed relative to the known SBU. Several packages built during compilation take much longer to build than binutils, including the

GNU C Library The GNU C Library, commonly known as glibc, is the GNU Project's implementation of the C standard library. Despite its name, it now also directly supports C++ (and, indirectly, other programming languages). It was started in the 1980s by ...

(rated at 4.2 SBUs) and the GNU Compiler Collection (rated at 11 SBUs). The unit must be interpreted as an approximation; various factors influence the actual time required to build a package.

Reception

LWN.net reviewed LFS in 2004: Tux Machines wrote a review about Linux From Scratch 6.1 in 2005: Tux Machines also has a second and a third part of the review.

References

External links

* *
Interview with Gerard Beekmans

Another interview with Gerard Beekmans
{{Linux Books about Linux Free software Works about free software Linux distributions without systemd